Notification of string changes

Author: Andrew Hancox
MDL-49101 core: Add a global admin setting config->requiremodintro
Removed requiremodintro setting from all core activity plugins and replace
with a single global setting.
Deprecated moodleform_mod::add_intro_editor and replaced with
moodleform_mod::standard_intro_elements


http://git.moodle.org/gw?p=moodle.git;a=commit;h=6398ff538763defce3c20263c381b38a37150537
http://github.com/moodle/moodle/commit/6398ff538763defce3c20263c381b38a37150537

+ 2.9 en [requiremodintro_desc,core_admin]
- 2.9 en [configrequiremodintro,core_admin]